From: Laszlo Nagy <gandalf@shopzeus.com>
To: Claus Guttesen <kometen@gmail.com>
To: pgsql-performance@postgresql.org
Subject: Re: Planning a new server - help needed
Date: Fri, 28 Mar 2008 11:47:27 +0100
Message-ID: <47ECCCBF.40908@shopzeus.com> (raw)
In-Reply-To: <b41c75520803280303h35e3b76asdf59dc16de45826a@mail.gmail.com>
References: <47ECB4F6.1040901@shopzeus.com>
<b41c75520803280303h35e3b76asdf59dc16de45826a@mail.gmail.com>
> I guess you mean postgresql 8.3.1? :-)
>
Yep. Sorry.
>> Question 3. FreeBSD 7.0 can use the ZFS file system. I suspect that UFS
>> 2 + soft updates will be better, but I'm not sure. Which is better?
>>
>
> I'd stick with ufs2 atm. There are some issues with zfs which probably
> have been ironed out by now but ufs2 has been deployed for a longer
> time. Performance-wise they are about the same.
>
Thank you. I suspected the same but it was good to get positive
confirmation.
>> Question 4. How to make the partitions? This is the hardest question.
>> Here is my plan:
>>
>> - the OS resides on 2 disks, RAID 1
>> - the databases should go on 8 disks, RAID 0 + 1
>>
>
> If you have enough disks raid-6 should perform almost as good as raid
> 1+0.
Hmm, I have heard that RAID 1 or RAID 1 + 0 should be used for
databases, never RAID 5. I know nothing about RAID 6. I guess I must
accept your suggestion since you have more experience than I have. :-)
Obviously, it would be easier to manage a single RAID 6 array.
> I've setup 11 disks in raid-6 plus one hotspare so I can get more
> space out of it. "Enough disks" are approx. eight and up.
>
The RAID controller that I have selected can only handle 8 disks. I
guess I need to find a different one with 16 channels and use more
disks. So are you saying that with all disks in a bigger RAID 6 array, I
will get the most out of the hardware? In that case, I'll try to get a
bit more money from the management and build RAID 6 with 12 disks.
I also feel that I need to use a separate RAID 1 array (I prefer
gmirror) for the base system.
Thanks,
Laszlo
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To: pgsql-performance@postgresql.org
Cc: gandalf@shopzeus.com, kometen@gmail.com
Subject: Re: Planning a new server - help needed
In-Reply-To: <47ECCCBF.40908@shopzeus.com>
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